If a woman does not immerse after her menstruation according to rabbinic norms, legislates Maimonides in 1176, she will lose her dower to her husband. In her lively and original work of social reconstruction, Eve Krakowski sees this law as a “milestone in the long and winding history of rabbinization.” Digging behind the law, one of Maimonides’s more aggressive legal reforms, she discovers fascinating and largely unseen traces of women’s folk piety.